Embodiments of the disclosure relate generally to power conversion systems and methods for converting and providing electrical power to feed an electrical system and, more particularly, to power conversion systems and methods with improved ride-through capability during transient events.
Renewable power, such as solar power generated by solar power generation systems, is becoming a larger source of energy throughout the world. A typical solar power generation system includes one or more photovoltaic arrays (PV arrays) having multiple interconnected solar cells. The solar cells of the PV arrays convert solar energy into DC power. In order to interface the output of the PV arrays to a power grid, a solar power converter is typically used to change the DC power from the PV arrays into AC power to feed a power grid.
Various solar power converter configurations exist for converting the DC power output from PV arrays into AC power. One implementation of a solar power converter has two stages including a DC-DC converter stage and a DC-AC converter stage. The DC-DC converter controls the flow of DC power from the PV arrays onto a DC bus. The DC-AC converter converts the DC power supplied to the DC bus into AC power that can be output to the power grid. Existing solar power converters further utilize power converter controller to regulate the DC-DC converter and the DC-AC converter to compensate for various system variables, such as DC bus voltage and AC grid voltage and frequency.
With the rapid growth of grid-connected solar power generation systems, solar power penetration into the power grid may have a significant impact on the grid voltage and frequency. A solar power generation system typically is required to remain connected to the power grid during transient events. One problem associated with certain transient events is that the DC-AC converter may be damaged when the current flowing through the DC-AC converter exceeds its hardware limitations. Another problem associated with transient events is that a power imbalance may appear at the DC bus when the output power of the grid varies significantly due to a change of the grid voltage and frequency.
Therefore, it is desirable to provide systems and methods to address the above-mentioned problems.